1. Field of the Invention
The present invention relates to digital-to-analog and analog-to-digital converter circuits and more particularly to converter circuits employing charge-transfer technology such as charge-coupled-device structures.
2. Description of the Prior Art
Digital-to-analog converters and analog-to-digital converters are very useful devices in data handling and data processing, and many different types of converters are available in varied technologies. A common type of converter is the resistive ladder type wherein a plurality of resistors of different weighted values corresponding to digital values are selectively combined to form a digital representation of the magnitude of an input analog signal. Another common type of converter circuit employs a plurality of capacitors arranged in weighted order magnitudes in combination with switching means such as transistors. An example of the latter scheme is described in U.S. Pat. No. 3,836,906 issued Sept. 17, 1974 to T. Ando et al. on an application filed Feb. 28, 1973 assigned to Sony Corporation.
Another prior art converter, a serial charge-redistribution digital-to-analog converter including two capacitors, is described in the publication "An All-MOS Charge-Redistribution A/D Conversion Technique" by Ricardo E. Suarey, Paul R. Gray and David A. Hodges published in the 1974 IEEE International Solid-State Circuits Conference Digest of Technical Papers, pg. 194.
The present invention is distinct from prior art converters in that charge-coupled-device circuits are employed wherein the charge transfer capabilities of such circuits permit efficient and accurate operation.